Methods and devices for safe operation of undersize autonomous vehicles on public roads

ABSTRACT

A miniature autonomous vehicle for operation on the public roads is disclosed. The small size allows efficiency for small payloads, but produces a danger of being overlooked by other vehicles. The size of the vehicle is less than driver operated vehicles and may be restricted to less than 200 pounds. Sensors determine the vehicles speed and the presence of environmental vehicles and use a processor to calculate the need for additional visibility. A visibility structure and support structure with lights or markers is controlled by the processor. The markers are controlled in their operation or position by the processor on the basis of the sensor data. Extending or raising and retracting or lowering the structure affects the air resistance and stability of the vehicle. The structure can be raised when the vehicle stops or is in traffic and lowered at road speeds in light or absent traffic.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/967,805 filed Dec. 14, 2015, now pending.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

BACKGROUND OF THE INVENTION

Field of the Present Invention

The field of the present invention is autonomous vehicle design anddesign for vehicles for use on public roads.

Field of the Present Invention

Background Concerning the Need for the Current Invention

Several companies have produced and tested autonomous or driverlessvehicles for use, including on public roads. These autonomous vehicleswill become commonplace in the near future and new uses will develop.They can offer efficiency in delivery since they eliminate the expenseof hiring a driver. To maximize adept maneuvering and to save on fueland other costs, such serviceable vehicles may be made smaller.

A very small vehicle can accomplish the mission of transportingdocuments or compact goods, yet potentially be unsafe to operate inordinary traffic because it may be overlooked by drivers or undetectedby sensors installed in either human operated or autonomous vehicles.Collisions could be frequent. The challenge of safely and legallyoperating extremely small vehicles in their working environment must beaddressed. One answer is the addition of structures, signs or visualdisplays that make the small vehicle sufficiently visible to operate onpublic roads without adding excessive weight.

What is the situation today regarding size? Small scooters and miniaturemotorcycles are usually forbidden on most roads. While some cars havesmaller heights and weights than usual, the space required for a humanoperator limits the miniaturization of the vehicle. In addition, humanpowered vehicles such as bicycles have a limited maximum speed by lawwhich reduces the problem of visibility of a fast approaching vehicle.What is the situation today regarding visibility? Devices such as turnsignals and brake lights in cars and trucks are usually at or above eyelevel or otherwise perceptible to a driver.

Current Technologies Related to the Current Invention

Autonomous vehicles are being produced and tested by several companies.They are able to operate on the public roads without human intervention.

Sensors, actuators, device controllers, data processing devices andsoftware to organize their interactions are highly developed, generallyavailable and documented for use by designers in any technologyrequiring them for development of a particular application.

There are many developed type of signs and visual displays and supportsfor them which are generally available.

Patent Publication to be Incorporated by Reference

U.S. Pat. No. 9,139,199 to Harvey published Sep. 22, 2015 isincorporated herein by reference in its entirety. Furthermore, where adefinition or use of a term in a reference, which is incorporated byreference herein, is inconsistent or contrary to the definition of thatterm provided herein, the definition of that term provided hereinapplies and the definition of that term in the reference does not apply.

BRIEF SUMMARY OF THE INVENTION

Disclosed is an autonomous, unmanned or driverless vehicle that may belimited in size to less than 200 pounds and designed to travel on publicroads. It features an elevated structure with visible elements ormarkers that are controlled by a data processing device which hassensors to detect other vehicles—their presence, speed and otherrelevant factors. It features a means to modify the visibility of themarkers based on the presence of other vehicles and the speed of this(invented) vehicle. There also may be a support structure that raisesthe visibility elevated structure above the vehicle to make it morenoticeable.

The claimed vehicle is further restricted in various claims. In onecase, the visibility structure is moved into a position of reduced airresistance by the data processing device on the basis of the data fromthe sensors. In another case, the height of the center of gravity ischanged by moving the elevated structure. This makes the vehicle morestable. In another case, the vehicle chassis is less than 24 inches inheight which necessitates the augmented visibility. In other cases, themarkers may be lights, electronic displays, or portions of the elevatedstructure.

The invention also includes a system for operating a driverless vehiclein ordinary traffic on public roads. It includes a structure with anextended and a retracted position. The visibility of the vehicle isincreased when the structure in the extended position. The airresistance is reduced when the structure is in the retracted position. Aprocessor controls the movement of the structure as it determines andassesses the vehicle's operating environment.

In various claims this system is further restricted to a vehicle with(a) a minimum of two additional square feet of visible structure above36 inches from the ground, (b) with less than two square feet visiblewhen retracted, and (c) with marker or visibility structure controlledby a processer and sensors from data comprising speed or presence ofanother vehicle.

The invention also includes a method of avoiding accidents by operatinga vehicle as described above, running a program on the processor todetect vehicles in the operating environment, and modifying thevisibility of the markers based on the presence and speed of anothervehicle. The additional restrictions described above are applied inother claims to the method of this paragraph.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The features and advantages of the various embodiments disclosed hereinwill be better understood with respect to the drawing in which:

FIG. 1 is a plan view of a simple autonomous miniature vehicle.

FIG. 2 is a side view of a simple autonomous miniature vehicle.

FIG. 3 is a side view of an autonomous miniature vehicle with chassis,visibility structure, and support levels.

FIG. 4 is a rear view of an autonomous miniature vehicle with chassis,visibility structure, and support levels.

FIG. 5 shows side and rear views of several variations in the visibilitystructure and support levels.

FIG. 6 shows a plan view of a situation where environments objects blockview of a simple autonomous miniature vehicle

FIG. 7 shows a side view where a simple miniature vehicle is not visibleto the driver of a nearby full size vehicle.

FIG. 8 is a diagram of control devices of an autonomous vehicle withcontrol of visibility structure and support.

FIG. 9 is a plan view of operation of a miniature autonomous vehicle intraffic with visibility on and structure extended.

FIG. 10 is a side view of operation of a miniature autonomous vehicle intraffic with visibility on and structure extended.

FIG. 11 is a plan view of operation of a miniature autonomous vehiclewithout traffic with visibility markers off and structure retracted.

FIG. 12 is a side view of operation of a miniature autonomous vehiclewithout traffic with visibility markers off and structure retracted.

FIG. 13 shows various visibility markers.

FIG. 14 shows visibility structures in deployed and retracted positions

DETAILED DESCRIPTION OF THE INVENTION AND EMBODIMENTS Definitions

MiniAV is a term used in this disclosure for an autonomous vehicledesigned and adapted for use on the public roads for which the basevehicle is substantially smaller than conventional driver operatedvehicles.

A vehicle configured for use on the public roads is one which hasstructural details designed and adapted to conform with the legal andoperational requirements of such use. It is designed to operate inordinary automobile and truck traffic as regulated by governmentalauthorities and is not restricted to off-road or privately controlledareas of operation.

A compete vehicle includes the base vehicle and any visibility systemand any support system for a visibility system.

An environmental vehicle is another vehicle which is nearby. It includesboth vehicles to which the visibility system and markers are directedand vehicles which have a potential effect on the safety and navigationof the miniAV. Environmental vehicles may be driver operated orautonomous.

A vehicle chassis includes the base vehicle itself (referenced as 20 inthe various figures), the payload and power systems but excludes anyvisibility structure or support structure for a visibility structure.

A visibility structure is a part of the miniAV designed to carry markersand be elevated above the chassis.

A support structure is a part of the miniAV designed to elevate avisibility structure above the chassis. It may be comprised of the lowerpart of the visibility structure. Low air resistance for a supportstructure is relative the air resistance of a larger chassis which wouldprovide the same height for the visibility structure.

Components of a miniAV with Visibility and Support Structures

The chassis of a miniAV is designed for efficient operation as anautonomous vehicle. It's comprises the motive power, control circuitsand equipment, and the components needed for road operation such aswheels and steering components. The payload is typically carried on orin the chassis. The size and weight is limited by considerations ofefficiency in cost of vehicle, energy use and other cost andenvironmental factors.

There is a need to deliver payloads of all sizes from small items suchas documents for repair parts, through medium items such a groceryorders to larger items requiring full size vehicles. This implies thatminiAVs would be required from as small a size as can be safely operatedon public roads up to sizes that blend into conventionally sizedvehicles. Experience with mass produced remote controlled cars indicatesthat reasonable ranges can be achieved with vehicles as small as 2pounds so the effective small limit is the mechanical ability to operateautonomously on roads with defects such as steel plates and potholes.Less sophisticated controls which may not avoid road defects wouldrequire a vehicle of about 50 pounds but more sophisticated controls mayallow much smaller vehicles.

The upper limit of miniAV size is approximately 200 pounds because avehicle of more than that weight is large enough to be seen in operationby other vehicles. This is approximately the weight of a moped with asmall driver which is the smallest conventional vehicle allowed inordinary traffic in most places. For efficiency and stability, a vehicleof this size would benefit from a reduced height of less thanapproximately 24 inches for the chassis component. Visibility andsupport structures above this height would be of limited weight and airresistance and in many cases movable to lower heights.

The visibility structure increases the visible size of the vehicle byextending into the line of sight of environmental vehicles. Toaccomplish this purpose, it must be a substantial distance above theground and in the current invention be elevated above the chassis. Theweight and air resistance of the visibility structure is limited toincrease the energy efficiency of the vehicle and the resistance tooverturning from road hazards.

The height zone from about 36 to 60 inches above the ground is criticalfor visibility of vehicles and their visual recognition. This is becausecommon small automobiles are about 60 inches tall and the eye level of amotorcycle or motor scooter driver is about 60 inches. Common blockingstructure such as traffic cones and barrels are about 36 inches inheight. A standard full size stop sign is required to be a octagonmeasuring 30 inches across with a surface area of about 6 square feet.As stop sign is an example of a sign with a requirement for beingnoticed as a primary safety consideration. Thus, it should be largerthan signs that merely convey information. Ideally, a visibilitystructure to be effectively seen should introduce 6 square feet ofvisible surface from a critical direction above 36 inches from theground. A smaller area would be more economical but structure of lessthan two square feet would be substantially less effective.

The visible markers of the visibility structure are those devices,components or features of the visibility structure which serve to beseen, detected or noticed by environmental vehicles. There are many kindof markers available in miniAV designs. The most basic is the surface ofthe visibility structure which may be made distinctive with paint,reflective patches or other surface treatments. Other markers includelights, display panels, reflectors, moving surfaces, and printed wordsor pictures.

A data processing device is used to control the markers. This device canbe located in the miniAV or remotely. It can be a separation process orfunction of a data processing device with other functions such as thegeneral operation of the miniAV. It uses data from sensors to determinethe situation of the miniAV and of environmental factors includingenvironmental vehicles. It uses this information to control some or allof functions including deployment or position of the visibilitystructure and visibility and operation of the markers.

A sensor or group of sensors is used to detect environmental vehicles.The raw data from the sensor or sensors is processed as necessary andgrouped with other factors to make a determination of the current andpossible projected situation with respect to environmental vehicles. Thesensor can use any appropriate technology to detect the environmentalvehicles. These technologies include radar, LIDAR, passive detection ofelectromagnetic waves of any frequency, active and passive sonar,receipt of transmitted signals. The sensors can be located on the miniAVor be in other places with data being communicated to the miniAVprocessor.

The environment in which a vehicle operates includes nearby objects orvehicles which are sensed, the configuration of the road as eithersensed, retrieved from an information store or communicated from anothersystem. It also includes the parameters of the current vehicle such asthe current speed.

Autonomous vehicles as a part of their operations sense vehicles aroundthem and develop sophisticated analyses of situations concerning thesevehicles for use in the detailed operation and navigation of thevehicle. When such information is passed from the processor or processin a processor of the vehicle control to the control processor for themarkers or visibility structure that is herein deemed to be data from asensor of environmental vehicles and can be used in determiningfunctions, actuation or positioning of markers and the visibilitystructure.

A sensor or group of sensors is used to detect the speed of the miniAV.This can be either the speed over the ground or the relative speed ofthe miniAV to some other vehicle or object. The raw data from the sensormay be processed by a processor to determine the speed. If a devicecontrolling the operation of the miniAV produces data or a signal tocontrol the speed of the miniAV, that device functions as a speed sensorand the data or signal can be used as a sensor by the data processingdevice controlling the markers. Similarly, information defined by thespeed of the vehicle by a vehicle operating processer can allow thatprocessor to function as a sensor to the marker or visibility controlprocessor.

A processor to modify the position or visibility of the markers orvisibility structure as a function of the sensor data would require asuitable program or algorithm. The algorithm would comprise severalsteps:

(1) Gathering information from the speed and vehicle presence sources orsensors.(2) Processing the information to determine vehicle speed and presenceof other vehicles from the raw sensor date.(3) Evaluating the need for visibility from the processed sensor data.This could be accomplished by evaluating a predetermined or generatedmodel of danger as a function of the input conditions.(4) Outputting a determination for use by actuators or controllers.

Various means to modify the visibility of the markers are provided invarious embodiments. One is to move the visibility structure from aretracted position, where it provides improved air resistance, roadstability, center of gravity height, efficiency or safe speed to thevehicle, to an extended position. In the extended position the markersare more visible because they are exposed or placed at a greater heightfrom the ground. Another means is to turn on, blink or flash markerswhich comprise lights. Still another means is to operate, flash orchange the contents of an electronic display. Some modifying means formarker visibility involve moving substructures of the visibilitystructure. Markers which are visible components can be deployed,exposed, waved, moved, aimed, uncovered or extended by mechanicalactuators under the control of the data processing device. The means ofmodifying the visibility of markers includes the whole variety oftechnologies and devices which actuate, energize, program, orcommunicate with markers for that purpose.

The modification of marker visibility can be a function of the presenceof other vehicles or the speed of the miniAV in various ways. Theinformation creating the functional relationship can be gathered bysensors or sources that are nearby and directly connected or remote andtransmitting the information over any type of communication channel. Theinformation may be processed, changed, augmented or limited as long asthe final result at the maker or visibility structure depends on thecondition of presence or speed.

Various embodiments use the means of modification as a function of thedetermination of the presence of one or more other vehicles and of thespeed of the miniAV.

In various embodiments a support structure connects the chassis with thevisibility structure. This may be distinct from the visibilitystructure, but it can also be merely the bottom part of the visibilitystructure itself. It raises the visibility structure sufficiently thatmarkers are placed into the field of vision of environmental vehicles ortheir drivers. Because most conventional street vehicles are at least 40inches high including the driver in the case of open vehicles andbecause many obstacles are about that height, markers should be raisedat least 40 inches from the ground. The support structure should providethe spacing with air resistance substantially less than a chassis ofcorresponding height.

An additional function of the support structure in some embodiments isto raise and lower the visibility structure for the purpose of increasedvisibility in the high position and decreased center of gravity in thelower position. In situations where enhanced visibility is not necessarythe lower center of gravity would make the vehicle more stable at highspeeds and resistant to overturn. The center of air resistance wouldalso be lowered, which also contributes to road stability. This allowhigher speeds to be safely used away from other vehicles.

The operational procedures and configuration of a MiniAV may bedifferent at road speeds and at stopping points. The visual structurecan be retracted wholly or partially in order to improve the structuraland aerodynamic properties of the complete vehicle. This improves thestability and economy of the vehicle in the situations where airresistance and resulting energy use, being proportional respectively tothe square and cube of the speed, are maximized. The extended visibilitystructure in slow speed or resting positions provides visibility in thesituations were that is needed.

Autonomous vehicles being equipped with sensors or systems to be awareof surrounding vehicles and information processing systems can evaluatethe need to extend the visibility system in particular situations. Theactual extension in situations where the vehicle is moving at asubstantial speed should be limited to speeds and degrees of extensionthat are determined to be stable, safe and not damaging to equipment.

Autonomous vehicles can use sensors to gather information aboutsurrounding vehicles and energize specific lights or other awarenessdevices associated with the visibility structure in situations where ahigher probability of unsafe interactions with surrounding vehicles aremore probable.

Detailed Description of the Drawing and Certain Embodiments

FIG. 1 is a plan view of a simple autonomous miniature vehicle with onlythe chassis component 20 from a simple and preferred embodiment of thecurrent invention. The envisioned vehicle is approximately 4 feet inlength, 3 feet in width and 24 inches in total height. It weighs about150 pounds without payload. This is sufficiently large to operate atnormal public road speeds and carry a reasonable payload with extremelyefficient energy use. Drive wheels 21 are powered by individual motors22 working from the energy of a battery 23. Control devices forautonomous operation 24 control both the drive motors and the steerablewheels 25. A payload 26 is placed in a center compartment for transfer.FIG. 2 shows a side view of the vehicle of FIG. 1 showing the samecomponents.

FIG. 3 (side view) and FIG. 4 (rear view) show a complete autonomousvehicle with the three levels envisioned by the current invention. Thesimple autonomous vehicle or vehicle chassis 20 of FIG. 1 and FIG. 2 hasthe additional levels of a visibility system 21 and a support system 22.The visibility system consists of two pods 35 with lights 33 on bothends and reflector strips or surfaces 34. The pods are supported by thestruts 32 that comprise the support level or system.

FIG. 5 shows side views of several different visibility and supportsystems for a small autonomous vehicle. Each pair of views shows avehicle chassis level 20, a visibility system level 30 and a supportlevel 31. Most of the systems have visibility lights 33 which aremodulated and operated by a data processing device on the basis of acombination of the speed and other conditions of the miniAV and thepresence of other vehicles. All of the visibility systems have a supportlevel or device 31 which could be designed to actively move and raiseand lower the visibility system or level on the basis of determinationsof a data processing device connected to sensors for speed or otherminiAV conditions and vehicle presence or other environmentalconditions.

The first vehicle system 40 has a fixed visibility structure 30 in twoparts. It has much less air resistance than a vehicle with aconventional structure of the same height, length and width. The centerof gravity is low due the nature of the visibility structure as awarning device made of hollow light weight materials. The visibilitylights 33 and reflective tape 34 provide a warning of the presence ofthe miniAV to other vehicles, especially human driven ones.

The second vehicle system 41 has a single thin visibility structure andsupport. This allows for high visibility from the sides and very low airresistance to forward motion. The sign shown is for advertising showinga way to share the function of high visibility with another purpose. Theadvertising could be an electronic display which shows advertising untilthe data processing device of the miniAV The display could replace theadvertising shown in low risk situations with warnings if deemedappropriate by the control computer based sensory data.

The third vehicle system 42 shows the support and visibility structuresreduced to minimal sizes. They could fold down or back for reduced airresistance at higher speeds or when away from other vehicles.

The fourth vehicle system 43 is an implementation for use where passiveopacity is required with low air resistance. The open slots allowairflow through the structure for reduced air resistance, but thecurvature prevents direct vision through the structure.

FIG. 6 shows a situation where the small size of a miniAV prevents thedriver of a conventional vehicle from seeing it and avoiding anaccident. A conventional vehicle 50 has stopped at a corner, and looksto the right before turning. The drive sees two other conventionalvehicles 51 but does not see the miniAV 52. The vision is blocked by twoobjects 53, one a trash can and the other a newspaper rack. Theseobjects are typically 36 to 40 inches high and do not block visibilityof conventional vehicles even if they are directly below the line ofvision. The driver of the conventional vehicle turns the corner and hitsthe miniAV 54. This is the situation to be avoided. A substantialvisibility structure is needed because of the high potential forconfounding objects. If the visibility is insufficient such accidentswill be too frequent.

FIG. 7 shows a side view of another situation where a miniAV may beoverlooked by a conventional vehicle driver. A conventional vehicle 50is stopped behind a miniAV 52. The line of sight 60 from the driver'seye 61 is blocked by the hood 62 of the conventional vehicle and thedriver, who may have barely noticed the miniAV, forgets it is there. Asa traffic light changes from red to green the conventional vehiclestarts off quickly and strikes the miniAV.

FIG. 8 shows a diagram of the operation of a control system for a miniAVwith a controlled visibility structure. The vehicle itself, also calledthe chassis, is controlled by a system 70 designed to control suchvehicles. In the embodiment diagrammed this is shown as being separatedfrom controls for the visibility system except for a shown and definedcommunication link 71. The AV control system 70 has attached sensors fornearby and other environment vehicles 73, vehicle speed 74 and generalexternal and internal conditions 75. In many cases sensors needed forthe operations of the vehicle autonomously are sufficient to control theoperations of the visibility module; and there is no need for additionalspecial purpose sensors. The autonomous vehicle data processing systemcan correlate this information and provide processed and interpreteddata for the visibility system.

The visibility system has a control processor 72 which receives reportedinformation which can include presence of nearby or approaching vehiclesand their relative locations and situations. The visibility systemprocessor makes decisions concerning deployment and operation of thevisibility structure and its associated lights, displays and devices.The structure or appropriate substructures is extended or retracted byactuators or motors controlled by included motor controls 76. Specificvisibility can include lights controlled by a light control 77,electronic displays controlled by a suitable controller 78 or otherdevices with a controller 79.

The system shown in FIG. 8 has separate processors connected by acommunications link for the autonomous operation of the vehicle and thevisibility system; but it would be convenient in many designs to combinethe functions in a single processor. The two functions could be separateprocesses in an operating or supervisory system running on the processorcommunicating by a facility of the operating system.

FIG. 9 shows a plan view of a miniAV operating on a road with traffic.FIG. 10 shows the same situation from a side view. The miniAV 20 isshown on a two lane road 91 with a substantial presence of environmentalvehicles 90 which may be conventional as shown or autonomous. It shouldbe noted that visibility is not just for the benefit of environmentaldriver operated vehicles; other autonomous vehicles, perhaps large ones,also may require line of site detection of the miniAV for safety. Asshown in FIG. 10 the visibility structure is extended under theseconditions.

FIG. 11 shows a plan view of a miniAV operating on a road withouttraffic going in the same direction. FIG. 12 shows the same situationfrom a side view. The miniAV 20 is shown on a two lane road 91 with onlyone environmental vehicle 90. Because that vehicle is traveling in theopposite direction and in a lane bound in the opposite direction, thedata processing device of the miniAV has deemed it unnecessary to raisethe visibility structure. As shown in FIG. 10 the visibility structureis retracted under these conditions. The miniAV is assumed to use itssensors to analyze the situation. Because a larger visibility structuremay require time to raise or lower, the decision may be made on a largertime scale than on the basis of one specific situation. Other kinds ofvisibility devices such as lights may have a fast response and bechanged based on vehicle by vehicle determination of the need.

FIG. 13 shows various methods of modifying the visibility of markersassociated with a visibility structure. The most basic way to do thisfunction is to move the visibility structure or one of its substructuresin and out of view. A visibility structure is shown in 130; it isdeployed or extended because it is visible; the corresponding retractedstructure is not shown because in this case it is not visible. The word“miniAV” is shown on its surface as a passive extension of its visibleeffectiveness. Other such passive extensions could include brightcolors, reflective tape and patterns and textures.

Another simple way to modify the visibility of markers is to turn on 132and off 131 lights on the visibility structure. The controls could do itin response to situations where increased visibility is decided to beput in effect because of conditions such a nearby vehicles or situationswith increased danger deduced by sensors. The implemented rules could beas simple as turning on lights when stopped near other vehicles or ascomplex as emergency “all out” operation when imminent collision isdetected. The light may be simply changed when conditions changed orblinked or flashed at different rates. There are many reasons that thelight should not be operated in the most conspicuous manner at alltimes. These include viewer fatigue, communication to surroundingdrivers of specific conditions, and the fact that the start of blinkingor flashing is more conspicuous than its continuance.

Various substructures of the visibility structure can be controlled.They can consist of items like extendable signs 135 which can be pivotedor telescoped into an extended, deployed and visible position 134 from aretracted position 133. There could also be visible elements that moveto attract attention and louvers, gobos or other visibility limiters toallow messages to be directed to specific vehicles.

Electronic display signs 138 are shown with one message 136 and a secondmessage 137. The signs can be controlled on the basis of the situationof the miniAV as in 136 or on the basis of the situation as sensed ofenvironmental vehicles 137. Different signs on different sides of theminiAV or otherwise directed to specific viewers can be differentlycontrolled.

Visible devices can be directed to specific environmental vehicles. Avisibility structure 139 is shown with a light 140 that can be directedto an environmental vehicle which need to be warned about the existenceof the miniAV. The receiving vehicle 142 has been deemed by the controlprocessor to require a special warning after its existence and situationare found through the use of sensors and the beam 141 is specificallydirected for this purpose.

FIG. 14 shows three variations of miniAVs with different operations todeploy or extend and retract visibility structures and substructures. Ineach case a visibility structure 30 is shown with a support structure31.

The first variation shows a visibility structure that is raised andlowered on hinged supports 156; it is shown retracted as 150 andextended as 151. The visibility structure is open in the middle to allowit to lower over the chassis of the miniAV. This reduces the airresistance of the combination by combining the frontal area of thechassis and the support structure. The center of gravity (retracted 157,extended 158) of the combination is greatly reduced by retractionbecause of the substantial lowering of the support structure.

The second variation shows miniAV with a visibility structure that isfolded when away from other vehicles or moving at substantial speeds;the vehicle is shown with the structure retracted as 152 and extended as153. The panels making up the visibility structure fold back in theretracted position and reduce the frontal area of the combined vehicleand it's air resistance. This allows substantial visibility structuresto be displayed in all four directions at low speeds and while thevehicle is stopped, with reduced frontal area when moving.

The third variation shows a miniAV with a flap 159 which can be raisedabove the main visibility structure; the vehicle is shown with the flapretracted as 154 and extended as 155. The flap is a substructure of thevisibility structure which provides increased visibility at low speedsand around other vehicles. It provides reduced air resistance whenretracted by either folding back on a hinge or telescoping in multiplesections out of the main visibility structure. If the miniAV is verysmall several folds or unfolds of the flap may be required to raise itto a sufficient height creating the desired visibility.

I claim:
 1. A method of avoiding accidents comprising: (a) operating adriverless first vehicle on public roads with the vehicle comprising: anelevated visibility structure with a visible marker controlled by a dataprocessing device with a first sensor to detect the presence of a secondvehicle and a second sensor to measure the speed of the base vehicle, asupport structure of low aerodynamic resistance connecting the vehiclechassis and the elevated visibility structure with the elevatedvisibility structure substantially raised above the vehicle chassis, adata processing device with a sensor to detect a second vehicle, (b)running a program on the data processing device to determine thepresence of a second vehicle, and (c) modifying the visibility of themarker as a function of the determination of the presence of a secondvehicle.
 2. The method of claim 1 wherein: the visibility structure ismoved into a position of reduced aerodynamic resistance by the dataprocessing device as a function of the determination of the presence ofa second vehicle.
 3. The method of claim 1 wherein: the height of thecenter of gravity of the first vehicle is changed by the data processingdevice as a function of the detection of the presence of a secondvehicle.
 4. The method of claim 1 wherein: the first vehicle has achassis of less than 24 inches in height.
 5. The method of claim 1wherein: the marker is controlled by a data processing device andcomprises a light which has an emission modified to modify thevisibility of the marker.
 6. The method of claim 1 wherein: the markeris controlled by a data processing device and comprises a graphicdisplay which is modified to modify the visibility of the marker.
 7. Themethod of claim 1 wherein: the visibility of the marker is modified atleast in part on the basis of the environment of the first vehicle. 8.The method of claim 1 wherein: the visibility of the marker is modifiedat least in part on the basis of the speed of the first vehicle.
 9. Themethod of claim 1 wherein: the marker comprises a portion of theelevated visibility structure which is moved under control of the dataprocessing device.
 10. A method of avoiding accidents comprising: (a)operating a driverless first vehicle with a visibility structure with afirst position and a second position wherein the operation is on publicroads and there may be a second vehicle present which is operated by adriver with a line of sight higher than the height of the first vehicle,(b) using a sensor to determine the presence of the second vehicle, (c)making the first vehicle visible to the driver of the second vehicle byraising the visibility structure from the first position to the secondposition wherein the first position is below the line of sight of thedriver of the second vehicle and the second position is above the lineof sight of the driver of the second vehicle, and (d) increasing theefficiency of the first vehicle by lowering the visibility structure tothe first position when the second vehicle is not present wherein thefirst vehicle with the visibility structure in the first position issubstantially more aerodynamically efficient than the first vehicle withthe visibility structure in the second position.
 11. The method of claim10 further comprising: increasing the stability of the first vehicle bylowering the visibility structure to the first position when the secondvehicle is not present, wherein the first vehicle with the visibilitystructure in the first position has a substantially lower center ofgravity than the first vehicle with the visibility structure in thesecond position.
 12. The method of claim 10 further comprising:increasing the stability of the first vehicle by lowering the visibilitystructure to the first position when the second vehicle is not present,wherein the first vehicle with the visibility structure in the firstposition has a substantially lower center of aerodynamic resistance thanthe first vehicle with the visibility structure in the second position.13. A method of safely operating a vehicle comprising: (a) operating adriverless first vehicle on public roads, (b) making a firstdetermination with a computing device and at least one sensor that thereis a risk that the first vehicle will not be seen by a driver of asecond vehicle which is a human driven vehicle, (c) moving a componentof the first vehicle with a first position and a second position fromthe first position to the second position to increase the visibility ofthe first vehicle to the driver of the second vehicle as a function ofthe first determination, (d) making a second determination with thecomputing device that the risk that the first vehicle will not be seenby the driver of the second vehicle has been reduced from the risk ofthe first determination, (e) moving the component as a function of thesecond determination from the second position to a first position toaccomplish at least one of a lower aerodynamic resistance by the firstvehicle and a lower center of gravity of the first vehicle.
 14. Themethod of claim 13 wherein: the first vehicle increases its efficiencywith the component in the second position from the efficiency of thefirst vehicle with the component in the first position as a result ofhaving a lower aerodynamic resistance with the component in the secondposition rather than with the component in the first position.
 15. Themethod of claim 14 wherein: at least one if the first determination andthe second determination is made at least in part on the basis theenvironment of the first vehicle as determined by the sensor.
 16. Themethod of claim 14 wherein: at least one if the first determination andthe second determination is made at least in part on the basis of thespeed of the first vehicle.
 17. The method of claim 13 wherein: thefirst vehicle increases its stability with the component in the secondposition from the stability of the first vehicle with the component inthe first position as a result of having a lower center of gravity withthe component in the second position rather than with the component inthe first position.
 18. The method of claim 17 wherein: at least one ifthe first determination and the second determination is made at least inpart on the basis the environment of the first vehicle as determined bythe sensor.
 19. The method of claim 17 wherein: at least one if thefirst determination and the second determination is made at least inpart on the basis of the speed of the first vehicle.